The Messel Pit represents a Konservat-Lagersttätte dating to the Eocene Epoch 47 million years ago. The site is in Hessen State in Germany, close to the city of Darmstadt. It is a disused oil shale quarry that was scheduled to become a landfill in the mid-1990s. Thankfully, due to public and scientific outcry, the site was designated as a UNESCO World Heritage Site in 1995. Ever since, there have been thousands of amazing and revolutionary discoveries. This article seeks to introduce this remarkable site and a glimpse into a lost world.
During the Eocene, global temperatures were much higher than they are today. The area that is now Messel was a volcanic lake surrounded by subtropical rainforests. The upper portions of the lake supported a wide diversity of organisms. The bottom waters where anoxic. This prevented bioturbation and inhibited bacterial decay leading to exceptional preservation. The lake would have periodically released toxic gases, in much the same way as Lake Nyos in northwest Cameroon, did in 1987 to lethal effect. The pit is comprised of oil shales. The rocks have a high-water content and any fossils recovered must be kept moist or else they will dry out and the specimen will be lost forever. They must also be stabilised with resin, in a process called the “transfer technique”.
The Messel Pit is unusual in that both plant microfossils and macrofossils are founds found in abundance. The types of plants found at Messel are ones you would expect from mid-to-low latitudes today. By studying the morphology of fossil leaves, it is possible to make assumptions about the local climate. Messel plants had long leaves with ‘drip tips’ and large stomata (that is, microscopic pores found on the epidermis of plants), which are commonly associated with warm, humid environments. One such group of tropical plants was the genus Canarium, which today are found across equatorial Africa, Indochina, Australia and the Pacific Islands.
The most common fossils at Messel are those of insects, especially beetles. Not only are anatomical details preserved in exquisite detail, but colour patterns are also present. Jewel beetles (Buprestidae) are distinguished by their preserved colour structures that, even after 47 million years, still shimmer with their original iridescence. The largest insect from the Messel was the ant genus, Formicium, which had a wingspan of up to 16cm. This ant would have behaved in much the same way as modern army ants, devouring anything unlucky enough to get in its path.
Fish are the most common vertebrates from the Messel Pit (Fig. 1). The most abundant were the gars and bowfins, which comprised up to 90% of fish diversity from some layers. The gar, Atractosteus strausi, had a massively built skull, a protruding crocodile-like snout and thick enamel covered scales. Gars are primitive bony fish that today are restricted to rivers in the Americas, slowly ambushing their prey. To deal with the low oxygen conditions in the lake, many bowfins and gar processed swim bladders specially adapted to allow them to ‘breath’ the air directly. Specimens showing signs of reabsorption of minerals on scale margins as a response to vitamin deficiency are commonplace. A single eel, closely related to the catadromous eels (ones that are born in the sea but spend their lives in fresh water) has been discovered, suggesting that the Messel lake was connected to the sea by rivers. Most fishes from the Messel lake are juveniles that perished before reaching sexual maturity.
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